Wireless sound transmission system and method

Abstract

A system for providing sound to at least one user, having at least one audio signal source for providing audio signals; a transmission unit with a digital transmitter for wirelessly transmitting the audio signals as data packets; at least one receiver unit with at least one digital receiver for reception of the audio signals from the transmission unit; a mechanism for stimulating the hearing of the user(s) according to audio signals supplied from the receiver unit. The transmission unit transmits each data packet in a separate slot of a TDMA frame at a different frequency in a frequency hopping sequence, in at least some of the slots, the audio signals are transmitted as audio data packets, the same audio packet being transmitted at least twice in the same TDMA frame without expecting acknowledgement, and the TDMA frames being structured for unidirectional broadcast transmission of the audio data packets.

What is claimed is: 
     
       1. A system for providing sound to at least one user, comprising:
 at least one audio signal source for providing audio signals; 
 a transmission unit comprising a digital transmitter for applying a digital modulation scheme in order to transmit the audio signals as data packets from the audio signal source via a wireless digital audio link; 
 at least one receiver unit for reception of audio signals from the transmission unit via the digital audio link, comprising at least one digital receiver; 
 means for stimulating hearing of at least one user according to audio signals supplied from the receiver unit; 
 wherein the transmission unit is adapted to transmit each data packet in a separate slot of a TDMA frame at a different frequency according to a frequency hopping sequence, 
 wherein, in at least some of the slots, the audio signals are to be transmitted as audio data packets, wherein a same audio packet is to be transmitted at least twice in a same TDMA frame, without expecting acknowledgement messages from the at least one receiver unit, 
 wherein the TDMA frames are structured for unidirectional broadcast transmission of the audio data packets, without individually addressing the at least one receiver unit, and 
 wherein each audio data packet comprises a start frame delimiter, audio data and a frame check sequence, and wherein each digital receiver of the at least one receiver unit is adapted to verify each received data packet by using the frame check sequence and to use the audio data of the first verified version of each data packet as the signal to be supplied to the stimulation means while not using the audio data of other versions. 
 
     
     
       2. The system of  claim 1 , wherein the same audio packet is to be transmitted at least twice in subsequent slots. 
     
     
       3. The system of  claim 1 , wherein each receiver of the at least one receiver unit is adapted to sleep at least during times when no data packets are to be expected. 
     
     
       4. The system of  claim 3 , wherein each receiver of the at least one receiver unit is adapted to wake up a given guard time period before expected arrival of an audio packet different from the previous audio packet. 
     
     
       5. The system of  claim 4 , wherein each receiver of the at least one receiver unit is adapted to wake up at a given guard time period before expected arrival of the repetition of the previous audio packet, if a start frame delimiter has not been received or if the previous audio packet could not be verified. 
     
     
       6. The system of  claim 5 , wherein each receiver of the at least one receiver unit is adapted to go to sleep again after a given timeout period after an expected end of transmission of the audio packet, if no audio packet has been received. 
     
     
       7. The system of  claim 6 , wherein each receiver is adapted to go to sleep again after a given timeout period after an expected end of transmission of the start frame delimiter of the audio packet, if a start frame delimiter has not been received. 
     
     
       8. The system of  claim 1 , wherein, in a first slot of each frame, a beacon packet is to be transmitted which contains information for hopping frequency synchronization. 
     
     
       9. A system for providing sound to at least one user, comprising:
 at least one audio signal source for providing audio signals; 
 a transmission unit comprising a digital transmitter for applying a digital modulation scheme in order to transmit the audio signals as data packets from the audio signal source via a wireless digital audio link; 
 at least one receiver unit for reception of audio signals from the transmission unit via the digital audio link, comprising at least one digital receiver; 
 means for stimulating hearing of at least one user according to audio signals supplied from the receiver unit; 
 wherein the transmission unit is adapted to transmit each data packet in a separate slot of a TDMA frame at a different frequency according to a frequency hopping sequence, 
 wherein, in at least some of the slots, the audio signals are to be transmitted as audio data packets, wherein a same audio packet is to be transmitted at least twice in a same TDMA frame, without expecting acknowledgement messages from the at least one receiver unit, 
 wherein, in a first slot of each frame, a beacon packet to be transmitted is provided which contains data necessary for synchronizing the network, and 
 wherein each receiver of the at least one receiver unit is adapted to wake up a given guard time period before expected arrival of the beacon packet of certain ones of the frames, while sleeping during expected transmission of the beacon packet of the other frames. 
 
     
     
       10. The system of  claim 9 , wherein each receiver of the at least one receiver unit is adapted to wake up at a given guard time period before expected arrival of beacon packets of frames having a sequence number which fulfills a given condition with regard to an address of the respective receiver unit. 
     
     
       11. The system of  claim 10 , wherein the at least one receiver unit comprise a plurality of receiver units, and wherein the transmission unit is adapted to send a message to a specific one of the receiver units by including the message into the beacon packet of a frame having a sequence number for which the given condition is fulfilled with regard to an address of the respective receiver unit. 
     
     
       12. A system for providing sound to at least one user, comprising:
 at least one audio signal source for providing audio signals; 
 a transmission unit comprising a digital transmitter for applying a digital modulation scheme in order to transmit the audio signals as data packets from the audio signal source via a wireless digital audio link; 
 at least one receiver unit for reception of audio signals from the transmission unit via the digital audio link, comprising at least one digital receiver; 
 means for stimulating hearing of at least one user according to audio signals supplied from the receiver unit; 
 wherein the transmission unit is adapted to transmit each data packet in a separate slot of a TDMA frame at a different frequency according to a frequency hopping sequence, 
 wherein, in at least some of the slots, the audio signals are to be transmitted as audio data packets, wherein a same audio packet is to be transmitted at least twice in a same TDMA frame, without expecting acknowledgement messages from the at least one receiver unit, 
 wherein, in a first slot of each frame, a beacon packet to be transmitted is provided which contains data necessary for synchronizing the network, and 
 wherein the at least one receiver unit comprise a plurality of receiver units, and wherein each receiver unit is adapted to wake up at a given guard time period before expected arrival of the beacon packet of frames having a sequence number fulfilling a certain global condition, in order to have all receiver units periodically listen to a same beacon packet. 
 
     
     
       13. The system of  claim 8 , wherein the transmission unit is adapted to receive in a second slot of each frame a control data packet from the receiver units requested by the transmission unit. 
     
     
       14. The system of  claim 8 , wherein a first slot of each frame is for multiplexing a beacon packet to be sent by the transmission unit and a control data packet to be received from the at least one receiver unit as requested by the transmission unit. 
     
     
       15. A system for providing sound to at least one user, comprising:
 at least one audio signal source for providing audio signals; 
 a transmission unit comprising a digital transmitter for applying a digital modulation scheme in order to transmit the audio signals as data packets from the audio signal source via a wireless digital audio link; 
 at least one receiver unit for reception of audio signals from the transmission unit via the digital audio link, comprising at least one digital receiver; 
 means for stimulating hearing of at least one user according to audio signals supplied from the receiver unit; 
 wherein the transmission unit is adapted to transmit each data packet in a separate slot of a TDMA frame at a different frequency according to a frequency hopping sequence, 
 wherein, in at least some of the slots, the audio signals are to be transmitted as audio data packets, wherein a same audio packet is to be transmitted at least twice in a same TDMA frame, without expecting acknowledgement messages from the at least one receiver unit, 
 wherein, in a first slot of each frame, a beacon packet to be transmitted is provided which contains data necessary for synchronizing the network, and 
 wherein the at least one receiver unit comprise a plurality of receiver units, and wherein each beacon packet includes at least one item of information relevant for an audio stream from the group of items comprising a description of encoding format, a description of audio content, a gain parameter, surrounding noise level; information relevant for multi-talker network operation, and control data for all or a specific one of the receiver units. 
 
     
     
       16. The system of  claim 1 , wherein the transmission unit is adapted to encode the audio data using ADPCM. 
     
     
       17. The system of  claim 1 , wherein the audio signal source is a microphone arrangement integrated into or connected to the transmission unit for capturing a speaker's voice. 
     
     
       18. The system of  claim 17 , wherein the transmission unit comprises an audio signal processing unit for processing the audio signals captured by the microphone arrangement prior to being transmitted. 
     
     
       19. The system of  claim 1 , wherein the transmission unit is adapted to establish the digital audio link at a carrier frequency in a 2.4 GHz ISM band. 
     
     
       20. The system of  claim 1 , wherein the transmission unit is adapted to be connected to an external audio device from the group of external audio devices comprising a mobile phone, an FM radio, a music player, a telephone and a TV device, as the audio signal source. 
     
     
       21. The system of  claim 1 , wherein the transmission unit is adapted to be connected via a digital audio link to an external transmission unit comprising a microphone for capturing a speaker's voice as the audio signal source. 
     
     
       22. The system of  claim 1 , wherein the at least one receiver unit comprise a plurality of receiver units, and wherein at least one of the receiver units is connected to or integrated into an ear-worn device, comprising the stimulation means. 
     
     
       23. The system of  claim 1 , wherein the at least one receiver unit comprise a plurality of receiver units, and wherein at least one of the receiver units is a neck-worn device comprising a transmitter for transmitting audio signals via an inductive link to an ear-worn device, comprising the stimulation means. 
     
     
       24. The system of  claim 1 , wherein the at least one receiver unit comprise a plurality of receiver units, and wherein the at least one receiver unit is connected to or integrated within at least one audience loudspeaker serving as the stimulation means. 
     
     
       25. A system for providing sound to at least one user, comprising:
 at least one audio signal source for providing audio signals; 
 a transmission unit comprising a digital transmitter for applying a digital modulation scheme in order to transmit the audio signals as data packets from the audio signal source via a wireless digital audio link; 
 at least one receiver unit for reception of audio signals from the transmission unit via the digital audio link, comprising at least one digital receiver; 
 means for stimulating hearing of at least one user according to audio signals supplied from the receiver unit; 
 wherein the transmission unit is adapted to transmit each data packet in a separate slot of a TDMA frame at a different frequency according to a frequency hopping sequence, 
 wherein in at least some of the slots, the audio signals are to be transmitted as audio data packets, wherein a same audio packet is to be transmitted at least twice in a same TDMA frame, without expecting acknowledgement messages from the at least one receiver unit, 
 wherein the TDMA frames are structured for unidirectional broadcast transmission of the audio data packets, without individually addressing the at least one receiver unit, and 
 wherein the at least one receiver unit comprise a plurality of receiver units, and wherein at least one of the receiver units is a neck-worn device comprising a transmitter for transmitting audio signals via an inductive link to an ear-worn device, comprising the stimulation means, and 
 wherein the at least one receiver unit comprise a plurality of receiver units, wherein each receiver unit comprises at least two digital receivers, each being connected to a common processing unit and an antenna and including a demodulator and a buffer, wherein each receiver is for receiving, verifying and buffering each of the audio data packets, wherein each receiver unit is adapted to send an interrupt request from at least one of the receivers to the processing unit to indicate when a packet has been received, and wherein the processing unit is adapted to read an audio data packet from a buffer of one of the receivers and, if the packet has been correctly received by that receiver, to flush the buffer of the other receivers and, if the packet has not been correctly received by that receiver, to read the audio data packet from the buffer of another one of the receivers.